Collaborative Research: Spatiotemporal observations of the demise of an ice sheet: Paleo perspectives from Baffin Bay, West Greenland.

格陵兰冰盖(GIS)今天正在缩小，以应对大气和海洋的变暖。如果完全融化，地理信息系统拥有的淡水足以使海平面上升7.4米(24英尺)。因此，了解中国如何应对气候变暖非常重要。这个项目将通过研究过去地理信息系统如何应对气候变暖来调查地理信息系统的脆弱性。在大约20,000年前的上一个冰河时代末期，地理信息系统的西部边缘进一步延伸到现在位置以西数百公里的巴芬湾。到1万年前，冰缘基本上已经退回到目前的海岸线范围内。目前还不清楚是大气变暖、海洋变暖，还是两者的某种组合导致了撤退。作为该项目的一部分，沿西格陵兰边缘研究的沉积物将建立在冰川消融期间地理信息系统退缩的时间、幅度和速度的区域差异。记录在相同沉积物中的地理信息系统变化和海洋变暖的相对时间，将提高我们对大冰盖过去和未来行为的理解。该项目更广泛的影响包括支持一名博士后研究员、三名研究生和本科生研究人员。此外，该项目还将支持根据拟议的研究考察制作一部外展影片。该项目还将促进以冰川消融为重点的高级本科课程的发展。为实现这一目标，一个海洋考察队将利用海底和海底下成像技术，并通过收集跨越上一次冰期结束至今的沉积岩芯，研究格陵兰西部的四个海槽口扇系统(地理信息系统在其近海延伸时在那里沉积了大量沉积物)。来自沉积物记录的生物、磁性、地球化学性质和物理性质将被用来检验主要假设：海洋终止冰川底部的海洋温度上升是冰盖不稳定的主要驱动因素。该项目将确定：1)西格陵兰边缘温暖的大西洋水入侵的时间和程度；2)冰缘退缩和海洋变化的阶段性；3)区域地质、地貌和冰动力学对冰缘退缩的影响。早期职业领导力(在资深导师的支持下)是该项目的核心，有三名美国助理教授和一名博士后研究员指导船上的操作，并带头开展探险后的科学研究。出海科学派对的一半将是研究生和本科生。从巴芬湾获得第一个美国沉积岩芯，并将岩芯和数据存档在美国的设施和数据库中，将为NSF社区提供多样化的高纬度研究机会，确保该项目的持续遗产。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Greenland Ice Sheet (GIS) is shrinking today in response to the warming atmosphere and ocean. The GIS holds enough freshwater to raise sea level by 7.4 meters (24 feet) if it melted completely. Thus, understanding how it responds to warming is important. This project will investigate GIS vulnerability by studying how the GIS responded to climate warming in the past. At the end of the last ice age, about 20,000 years ago, the western GIS margin extended farther into Baffin Bay, hundreds of kilometers west of its present position. By 10,000 years ago, the ice margin had largely retreated to within the current coastline. It is unclear if a warming atmosphere, a warming ocean, or some combination of the two is responsible for the retreat. Sediments studied along the West Greenland margin as part of this project will establish regional variations in the timing, magnitude, and rate of GIS retreat during the deglaciation. The relative timing of GIS changes and ocean warming, recorded in the same sediments, will improve our understanding of the behavior of large ice sheets in the past and future. The project broader impacts include support for a postdoctoral researcher, three graduate students, and undergraduate researchers. In addition, the project will support production of an outreach film based on the proposed research expedition. The project also will facilitate development of an upper-level undergraduate course focused on the deglaciation. To accomplish this goal, an oceanographic expedition will study four West Greenland trough mouth fan systems (where the GIS deposited large volumes of sediment when it extended offshore) using seafloor and sub-seafloor imaging techniques and by collecting sediment cores spanning the end of the last ice age to present. Biological, magnetic, geochemical, and physical properties from the sediment records will be used to test the primary hypothesis; that increasing ocean temperature at the base of marine terminating glaciers is a major driver of ice-sheet instability. The project will establish: 1) the timing and extent of warm Atlantic water incursion along the west Greenland margin; 2) the phasing of ice margin retreat and ocean change; and 3) the influence of regional geology, geomorphology, and ice dynamics on ice-margin retreat. Early career leadership (supported by senior mentors) is at the heart of this project with three US-based assistant professors and one post-doctoral researcher directing shipboard operations and spearheading the post-expedition science. Half of the sea-going science party will be graduate and undergraduate students. Acquisition of the first US-based sediment cores from Baffin Bay and archival of the cores and data in US facilities and databases will provide diverse high-latitude research opportunities to the NSF community, ensuring the continuing legacy of this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.